There is usually a minimum amount that you have to deposit (usually $500) to start if off. A CD means Certificate of Deposit. You're basically promising the bank that you'll leave 'X' amount in the bank for a specified amount of time. The longer you leave the money in the CD, the higher the interest rate you'll get. The larger the amount and the longer the time it's in there, the more money you'll receive in interest.
There is no risk in a CD because it isn't tied to any stocks, bonds, or mutual funds. It is the bank paying you interest for letting them use your money. Remember though that if you're going to deposit the money it becomes "frozen" meaning you can't touch it until the maturity date of the CD. If you do touch it, there is usually a penalty that you have to pay for taking money out before the maturity date.
CDs are great for those that are just learning about investing and have extra money that they're not going be using for a while.
It is risk free because it is an insured deposit (not really an investment, as such). If you need to withdraw the funds early, there is a small penalty, like 3 months interest (big whoop). My credit union allows me to add to an existing CD - which I do if that rate is higher than the current rate, or I want my money back soon ( i e when this existing CD matures in the near future.) Unredeemed CD's just roll over for the same term, but at the current interest rate.
{ Series EE savings BONDS double after x amount of years (and x is very big right now).}
You can purchase a CD in a specific amount for a specific length of time at a specified interest rate. For instance if you purchased a $1,000. CD for 1 year at 2% interest the CD would mature in 1 year and be worth $1,020. CD's are insured but cannot be redeemed prior to the due date.
You are over ambitious expecting investment to double in months. If you invest in the stock market you could do better than 2% or so but there is no guaranties and you could lose as well as earn a profit.
There's no "doubling" involved. A bank CD is simply a time deposit savings account. You agree to leave the money in the account for the term of the CD. In return, the bank pays a higher interest rate than it would offer for a regular demand savings account. The longer the term, the higher the interest rate. You can get CDs for terms of anything from 30 days to 10 years.
::sigh:: why don't you do a quick internet search or call a bank and ask them
I know the answer I just do not feel like telling you
okok